On the topic of the Galactica's size, I thought I'd share the most comprehensive study I've seen done on this topic. It's very interesting if you're in to this sort of thing.
The article is here:
http://www.merzo.net/
but the site does not allow me to link directly to the article. so there are steps.
Go there, click on the 2X scale option,
find the Galactica and click the link beneath it....
